Hollow beam structures for axles are desirable over solid beam structures due to their reduced weight. The hollow structures typically provide sufficient strength due to their large section modulus with efficient distribution of material. Hollow beam structures are particularly useful for heavy duty truck applications. Typically, either round or rectangular shaped beams are used, which offer sufficient bending strength overall; however, additional structures may be required at locations where other vehicle components are mounted, such as suspension components for example, to provide increased strength.
One proposed solution has been to use local stiffeners to strengthen the mount interface for attachment of suspension components. As the hollow beam structures are closed, it is often difficult to provide efficient local stiffeners in terms of both weight and cost. One known configuration provides a two-piece structure that forms the hollow beam structure. A C-shaped beam portion is utilized and a bottom plate is subsequently attached to form the final enclosed hollow beam structure. Prior to attachment of the bottom plate, a tube is positioned within the hollow cavity such that tube ends abut against inner wall surfaces of the hollow beam structure. The tube is then welded to the wall surfaces and then the bottom plate can be installed. This process is time consuming and adds cost and complexity to the assembly process.